Electric motor.



No. 850,203. PATENTED APR. 16, 1907. R. E. BARKER.

ELECTRIC .MOTOR.

APPLICATION FILED MABJZ, 1906.

WITNESSES- INVENTDR. WWW E7 RALPH E.BARKER- UNITED STATES PATENT ;()FFICE.

' RALPH E. BARKER, OF LYNN, MASSACHUSETTS, [ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION NEW YORK.

ELECTRIC moron.

no. cameos.

Specification of Letters Patent.

Patented April 16,1907.

a Applicsh'on filed March 12, 1906. Serial No. 305,463.

To all whom it may concern.-

it known that I, RALPH E. BARKER, a citizen of the United States, residing at Lynn,

county of Essex, State of Massachusetts,

have invented certain new and useful Imrovements in Electric Motors, of which the ollowing is a specification.

' My invention'relates to electric motors of the type'provide'd with voltage-controlling means; and its object is to provide simple a means for insuring the starting of such motors with a high torque.

While my invention in its broader aspect a is not limited to any articular type of moso as 'to control the speed of the .motor.

' When such an arrangement is employed, if

, from the motor.

the switch is left ina low-speed position, so that. most of the inductance is in the motorcircuitfand if the startin friction or other load is comparatively hig the -motor may fail to start. It oftenhappensrthat a fanmotor, with its speed-cgntrolling switch, is installed on the wall' of -some inaccessible place and is wired up to an ordina snapswitch, which may be a considerable istance Under such conditions it is evident that some provision-is desirable for makingthe' motor start even though all of the speed-regulating coil is in series with v the motor-windings.

My invention consists in providing the motor with automatic means for short-circuiting the speed-regulating inductance at starting, and for this purpose I em by a centrifu ally-actuated switch carried hy the rotor. en the motor is at rest, the ins .ductance. in series with it is short-circuited by the switch, which .0 ns when the motor comes up to speed. for any reason the motor stops, the shortcircu1ting switch closes, shunting vo tage when the circuit is again closed, and thus to develop its maximum starting ele-- ment.

cable to single phasethe entire inductance, leavin the motor in position to receive full-line My invention will best be understood by reference to the accompanying drawings, in which"' Figure l shows a single-phase inductionmotor arranged in accordance with my invention, one end bearing being removed. Fig. 2 shows a perspective view of the end bearing, and-Fig. 3 is a diagram of circuit connections.

In the drawings, A re resents the rimary member of the motor, w ich is-providhd with the field-coils B. The field-poles carry the short-circuited conductors C, which distort the field at. starting, so as to give a starting torque.

D represents the rotor, which is shown as of the squirrel-cage type.

A motor constructed as, shown in Fig.1

has at best a comparatively low starting-- tor ue, as is well understood in the art. Wit normal voltage at'the motor-terminals this torque is sufficient for many urposes.

as, for instance, driving a fan. I however,

the'terminal volta e is greatly reduced, the

motor may be una le to start under the fric tion-loa'd of the fan. a

E E represent contacts pivoted at e'e on I the rotor and provided with sprin s e, which when the motor is at rest hold t e contact membersv E ineng'agement with the station. ary contacts F, which are supported by the member G,fas shown in Fig. 2. These 0on tacts' are indicated in dotted lines in Fig. 1.

Four contacts F are; employed, opposite contacts be'im cross-connected so as to form two, pairs. lfach pair is connected to a ter-' minal of an inductance I, which is in series with the primary winding B of the motor.

H represents a switch which is arranged to cut varying ortions of the inductance I out of circuit. 11 the position shown in Fig. 3 all of the inductance I is cut out of circuit by the switch H, so that the motor is directlryi connected across the line. If theswitch is rotated in a counter-clockwise direction, successive portions of the inductance will be cut into circuit, thereby lowering the voltage impressed on the motor-terminals. In this manner the speed of the motor ma be conveniently regulated, but if the switc H were left in a low-speed position, so as to include the greater portion of the inductance I in circuit with the motor, and current were then supplied to the motor to start it the voltage impressed on the motor-terminals would be a so much reduced that the motor which at best has a small starting tor ue might not start at all. By employing t e centrifugal contacts E, however, the inductance I is always short-circuited at starting, since these contacts bridge the stationary contacts F, connected to the inductance-terminals. As the motor comes up to speed the contacts E are thrown outwardly by centrifugal force, thereby removing the short-ci'rcuitfrom the inductance, so that it comes into play to control the motor speed.

I do not desire to limit myself to the particular construction and arrangement of parts here shown, but aim in the appended claims to.cov er all modifications which are within the scope of my invention.

What I claim as new, and desire to secure by Letters Patent of the United States, is

' 1. In combination with an electric-motor,

an impedance normally in series with said motor, and automatic means for" short-circuiting said impedance at starting.

2. In combination-with an'electric' motor, an impedance normallyin series with said motor, and a centrifugally-actuated switch connected to said motor and arranged to short-circuit said impedance when the motor is at rest.

3. In combination with an electric motor, animpedance in series with the motor, a manually-operated switch arranged .to cut variable portions of said impedance out of circuit, and means for automatically shortcircuiting said impedance at starting.

4. In combinationwith an electric motor, an impedance inseries with the motor, a manually-operated switch arranged to cut variable portions of said impedance out of circuit, and a centrifugally-actuated switch connected to saidmotor and arranged to shortcircuit said impedance when the motor is at rest.

'5. In combination with an electric m0tor,.- .manually-operated means for controlling the voltage impressed on the motor, and automatic means for rendering said manuallyoperated controlling means inoperative at starting.

6. In combination with an electric motor, manually-operated means for controlling the voltage'impressed on. the motor, and a centrifugally-actuatcd switch connected to the motor and arranged to render said manuallyoperated controlling means inoperative when the motor is at rest.

7. In combination with an inductionmotor, an inductance in series with the motor, a manually-operated switch arranged to cut variable portions of said inductance out of circuit, and means for automatioallyshortcircuiting said inductance at starting.

8. In combination with an inductionmotor, an inductance in series with the motor, a manually-operated switch arranged to cut variable portions of said inductance out of circuit, and a centrifugally-actuated switch connected to said motor and arranged to short-circuit said inductance when the motor is at rest.

9. In combination with an inductionmotor, an'inductance in series with the motor, stationary contacts connected to terminals of said inductance, 'and a contact member'carried by the rotor of the motor arranged to [bridge said stationary contacts when the motor is at rest and to be moved out of engagement therewith by centrifugal force when the motor speeds up.

'10. In combination with an inductionmotor, an inductance in series with the motor, a manually-operated switch arranged to cut variable portions of said inductance out of circuit, stationary contacts connected to terminals of said inductance, and a contact member carried by the rotor of the motor arranged to bridge said stationary co'ntacts when the motor is at rest and to be movedout of engagement therewith by centrifugal force whenthe motor s eeds up.

In witness whereof I have ereunto set my hand this 9th day of March, 1906.

RALPH E. BARKER.

' Vitnesses:

JOHN A. MoMANUs, J12,

HENRY O. VVEsTENDnnP. 

